Slack-adjuster for railway-car brakes



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J. GRIER.

SLACK ADJUSTER FOR RAILWAY CAR BRAKES.

No. 570,925. Patented Nov, 10, 1896.

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SLAGKADJUSTER FOR RAILWAY GAR BRAKES.

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No. 570,925 Patent'ed'Nov. 10,1896.-

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UNITED STATES I PATENT Y OFFICE.

MATTHEW J. GRIER, 0F PHILADELPHIA, PENNSYLVANIA.

SLACK-ADJUSTER FOR RAILWAY-CAR BRAKES.

SPECIFICATION forming part of Letters Patent N 0. 570,925, dated November 10, 1896.

Application filed March 9 1896. Serial No. 582,3 84. (No model.)

To all whom it may concern:

Be it known that I, MATTHEW J. GRIER, a citizen of the United States, residing in Philadelphia, Pennsylvania, have invented certain Improvements in Slack-Adjusters for Railway-Oar Brakes, of which the following is a specification.

The object of my invention is to provide the braking mechanism of railway-cars and other vehicles with means for automatically taking up the slack occasioned by the wear of the brake-shoes, stretching of the rods, (to. To accomplish this, I use, in connection with the ordinary levers of the braking mechanism known, respectively, as the live and dead levers, or with the brake-beams in certain classes of trucks, an interposed lever, which, by the action of the take-up mechanism, changes its position bodily on the truck, and which for convenience I call a walking-lever. This interposed lever,when used in connection with the ordinary railway-car truck, is so connected with the brake-beam levers that at the time of application of power to the brakes both of said brake-beam levers will be put into action at the same moment, thus making them both acting or live levers, in contradistinction to the ordinary method of operation, in which one lever is active (live) and the other is relatively passive, (dead) One of the brake-beam levers is connected with one end of the walking-lever and the other brake-beam lever is connected with the opposite end of the same. The walking-lever has two fulcra, neither of which is fixed, these fulcra alternating in their functions according as power is applied to the brakes or the latter are released. If the power is applied to the walking-lever, it is transmitted directly to the brake-beam levers, or if applied first to one of the latter it is transmitted to the walking-lever and thence to the opposite brake-beam lever. The object of the walking-lever is partly to put both brakebeam levers into action at the same time, thus reducing the thrust of the piston-rod of the brake-cylinder, and further to assist in taking up the slack due to wear and tear of the brake mechanism, to maintain the various positions of one or both brake-beam levers in taking up the slack, and to automatically permit of free movement of the car-wheels when the brakes are released. To take up any existing slack in the brake-gear, it is necessary that the advance movement of the brakebeam levers should be wholly or partially maintained. Hence I prefer to use for this purpose a pair of racks which may both be carried by the walking-lever, or which may be carried one by the walking-lever and one by one of the brake-beam levers. The preferable plan is to attach both racks to the walk ing-lever at points between the points of attachment of the rods which connect said walking-lever to the brake-beam levers. The racks are loosely attached in order to permit free movement of the walking-lever, and these attachments constitute the fulcra of said walking-lever, so that if it be moved in one direction one attachment becomes the fulcrum controlling that particular movement, its rack remaining stationary, while the other rack is advanced as much as the slack will permit, its teeth engaging with the retainer and holding it in the new position. When the walking-lever is moved in the opposite direction, it reverses the action of the racks, the one which was formerly moved now being stationary and the one which was formerly stationary now being moved and having its movement held by the retainer. In consequence of this construction intermittent movements of advance are given to the walking-lever, and the brake-beam levers are correspondingly affected, so as to take up the slack.

In order to insurea straight-line advance of the Walking-lever in its forward or backward movements, a slotted guide is desirable, this guide preferably controlling one of the rack-pins. 1

The details of the device may be varied as may be demanded by the varying plan of the trucks to which said device is attached, and the invention is not limited in its application to brakes such as are used upon steam-cars, but may by slight modifications or arrangement of parts be applied with equally good results to the brake structures used upon street-cars.

Having thus given a general description of my invention and its purpose, I will now. describe the same more in detail, referring to the accompanying drawings, in which- Figure 1 is a perspective view of part of an ordinary four-wheeled truck having braking mechanism provided with slack-ad j usting devicesin accordance with myinvention. Figs. 2 and 3 are plan views of the same with the parts in different positions, and Figs. &, 5, 6, and '7 are views illustrating various modifications of my invention.

In Fig. 1 the frame of the truck is represented at 1, the axles being shown at 2 and the wheels at 8, while the brake-beams are represented atei, enough of each brake-beam being shown to illustrate the brake-shoe 5, the hanger-link 6, and the retracting-spring 7. Each brake-beam has a projecting lug or bracket, to which is hung a lever, that of one brake-beam being represented at 8 and that of the other brake-beam at 0, the short arms of these levers being connected by a rod 10, while the long arm of the lever 8 is connected by a rod 11 to one end of a lever 12, the opposite end of the latter lever being connected by a rod 13 to the long arm of the lever 9. This lever 12 is the interposed or walking lever to which reference has heretofore been made, and it is in the present instance connected to the rod 14, which leads to the piston-rod of the power-cylinder, to the chain of the hand-brake, orto any other form of powerapplying device.

Hung to the lever 12 are two rack-bars 15 and 16, which are adapted to engage with the opposite legs of a yoke 17, against which they are pressed by an interposed spring 18, so that said legs of the yoke serve as retainers for the respective rack-bars.

The pin which attaches the rack-bar 16 to the lever 12 enters a slot 19 in a plate 20, which is secured to the truck-frame in any convenient position, this plate being widened or enlarged at one end so as to carry the yoke 17, so that the application or removal of the slack-adjusting device can be very readily effected.

lVhen power is applied to the rod 14:, it tends to move the lever 12 in the direction of the arrow, Fig. 2, and hence imparts a pull upon the rack-bar 16 in the direction of the arrow. (Shown in Fig. 2.) As said rack-bar is prevented from moving in this direction, however, by reason of its engagement with the yoke 17, the attaching-pin of said rackbar becomes the fulcrum for the lever 12. Hence the rods 11 and 13 are drawn in the direction of their respective arrows, Fig. 2, and the rack-bar 15 is moved in the direction of its arrow. These movements continue until they are arrested by the application of the brake-shoes to the wheels, or until the completion of the stroke of the power device, if the slack of the brake-gear is greater than can be taken up by one movement. \Vhen the pull upon the rod 14- ceases, the brakebeams are retracted by the action of the brake-beam springs 7, or, in the absence of the latter, by the action of gravity, and the lever 12 is moved in a direction the reverse nected by rods 22 to a beam 23.

of that indicated by the arrow in Fig. 2. The pivot-pin of the rack-bar 15 now becomes the fulcrum of the lever and the rack-bar 16 is advanced and retained in its position of advancement by engagement with the yoke 17, and these operations are repeated on each operation of the power 'device for applying the brakes, the result being that the lever 12 gradually advances or travels forward until the slack in the gear is entirely taken up and the shoes on each release of the brakes only fall far enough away from the wheels to free them from contact. Fig. 3 shows the position of the parts after an excessive amount of slack has been taken up.

Various modifications are possible within the scope of my invention, and some ofthese modifications I will now proceed to describe.

In the construction shown in Fig. 4: the lever 12 carries a pair of pawls 15 and 16, these pawls engaging with racks 15 and 16 formed on the opposite edges of a plate 20, which has the slot therein for the guidance of a pin 011 the lever, the operation of this de vice being substantially similar in effect to that of the device shown in Figs. 1 and 2.

In the construction shown in Fig. 5 a lever 12, having only one rack 16, is employed, the other rack 15 being carried by the upper end of the lever 8 and engaging with a suitable retainer on the truck-frame. In this case the second fulcrum of the lever 12 is at the point of attachment of the rod 11, which connects said lever to the lever 8, the point of attachment of the rack-bar 16 serving as the fulcrum when power is applied and the point of attachment of the rod 11 serving as the fulcrum for the lever 12 when the brakes are released.

In Figs. 6 and 7- I have shown the application of my invention to two well-known forms of street-car-brake mechanism. In the construction shown in Fig. 6 the brake-beam for the wheels at one end of the truck is represented at 21, the beam having brakeshoes for the wheels at the other end of the truck not being shown, but being in practice con- A lever 24 is hung to a lug on the beam 21 and is connected by a link 25 to a walking-lever 12 which carries a pair of rack-bars 15 and 16 adapted to engage with a yoke 17 on a plate 20, secured to the beam 23. When the brake rod is pulled in the direction of the arrow, therefore, the brake-beam 21 is thrust forward in the direction of its arrow and the link 25 is pulled in the reverse direction, thereby imparting corresponding movement to the lever 12 and causing the rack-bar 15 to be thrust forward in the direction of its arrow, so as to cause an advance of its pivot, which becomes the fulcrum for the lever 12 on the release of the brakes. This movement causes the rack-bar 16 to be thrust forward and these movements continue until the beams 21 and 23 are drawn together sufficiently to take up the slack. In the construction shown in IIO Fig. 7 the brake-beam 21 carries a lever 24:, which is connected by a link 25" directly to thebeam 23, the latter being outside of the brake-beam 21 instead of inside of the same, as in Fig. (3, and being connected to the brake-beam at the opposite end of the truck by rods 22. In this case the lever 52? is connected by rods 26 to a walking-lever 12 which is suitably guided upon a plate 20 secured to the truck-frame, and carries two rack-bars 15 and 16, engaging with a yoke 17 on said plate. In this case, as before, the lever 12 advances on the successive operations of the brake mechanism, so as to have the effect of drawing the brake-beam 21 nearer to the wheels and forcing the beam 23 away from the beam 21, so as to effect a corresponding approach of the opposite brakebeam to its wheels, the result being that the slack in the brake gear will be taken up as soon as it becomes sufficient in extent to permit a movement of the primary acting rackbar of the walking-lever to the extent of a single tooth of the same.

Having thus described my invention, I claim and desire to secure by Letters Patent l. Slack-adj Listing mechanism for railwaycar brakes, consisting of a lever independent of the brake-beams or brake-beam levers of the car but having connection therewith so as to be operated on each application of the brakes, said lever being combined with a pair of racks and having two alternately-acting fulcrums whereby, in case of undue slack in the gear, there is on the application of the brakes an advance of one rack, and on the release of the brakes, an advance of the other rack, substantially as specified.

2. Slack -adjusting mechanism for carbrakes, consisting of a lever independent of the brake-beams or brake-beam levers, but

having connection therewith, whereby it is operated on each application of the brakes, said lever having alternately-acting fulcrums and being combined with a pair of racks, one of which, in case of undue slack in the gear is advanced when the brakes are applied, and the other when the brakes are released, said lever being guided so that its advance movements are in straight lines, substantially as specified.

3. Slack adjusting mechanism for carbrakes, consisting of a lever independent of the brake-beams or brake-beam levers but having connection therewith, and carrying a pair of racks each engaging with a suitable retainer, said racks being constructed and disposed as described whereby the connection of first one rack and then that of the other rack with the lever constitutes the fulcrum on which said lever swings, substantially as specified.

4. Slack adjusting mechanism for carbrakes, consisting of a lever connected at one end to the brake-beam lever at one end of the truck, and at the other end to the brakebeam lever at the opposite end of the truck, said lever having alternately-acting fulcrums and being combined with racks engaged by suitable retainers and so disposed in respect to the lever that, in case of undue slack in the gear one rack will be advanced by movement of the lever in one direction and the other by movement of the lever in the opposite direction, substantially as specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

MATTHEW J. GRIER. I Witnesses FRANK E. BECHTOLD, J os. H. KLEIN. 

